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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research » Research » Publications at this Location » Publication #323438

Research Project: Production and Disease and Pest Management of Horticultural Crops

Location: Southern Horticultural Research

Title: Effect of cultural practices and fungicide treatments on the severity of Phytophthora root rot of blueberries grown in Mississippi

Author
item Smith, Barbara
item Miller Butler, Melinda

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2016
Publication Date: 4/4/2016
Citation: Miller-Butler, M., Smith, B.J. 2016. Effect of cultural practices and fungicide treatments on the severity of Phytophthora root rot of blueberries grown in Mississippi. Abstract Book XI International Vaccinium Symposium, University of Florida Gainesville, FL. Page 178.

Interpretive Summary:

Technical Abstract: Effect of cultural practices and fungicide treatments on the severity of Phytophthora root rot of blueberries grown in Mississippi Melinda Miller-Butler and Barbara J. Smith ABSTRACT. Phytophthora root rot is an important disease of blueberries especially when grown in areas with poor drainage. Reliable management strategies are needed for this disease. Two studies were conducted to evaluate the effects of cultural practices and fungicide treatments on Phytophthora root rot severity of blueberries planted in Phytophthora cinnamomi infested soil. Plants of one-year-old ‘Star’ or two-year-old ‘Legacy’ were transplanted into flat or raised beds (whole plots) fertilized with 0.5x, 1x, or 2x levels of nitrogen as urea (subplots). Within subplot treatments were soil amendments (pine bark, peat, none) or fungicide treatments [Agrifos (phosphorous acid) foliar, Aliette (aluminium tris) foliar and drench, Ridomil Gold (mefenoxam) drench]. Plant vigor was rated twice a year and top and root weights were recorded at the conclusion of each study. Plants in the ‘Star’ study were grown for four years and those in the ‘Legacy’ study were grown for two years. ‘Star’ plants grown for two years on raised beds were more vigorous and had a greater percentage living plants than those grown on flat beds, but there was not a significant difference in vigor or percentage living plants due to nitrogen level. After four years ‘Star’ plants in the Agrifos foliar, Aliette foliar and drench, Ridomil Gold drench, and bark treatments had the highest top and root weights and vigor scores, but there was no significant difference in vigor or top weight of plants due to bed height or nitrogen level. After two years plants in the ‘Legacy’ study that were fertilized with urea at the 2x rate had the greatest top weight. Those treated with Agrifos foliar, Aliette foliar, and Ridomil drench had the highest vigor scores and top weights. There were no significant differences in vigor or top weight due to bed height. KEYWORDS. Phytophthora cinnamomi, Vaccinium corymbosum, disease control